﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#nullable disable

using System.Collections.Specialized;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Design;
using System.Runtime.InteropServices;
using System.Windows.Forms.Automation;
using System.Windows.Forms.Internal;
using System.Windows.Forms.Layout;
using static Interop;

namespace System.Windows.Forms
{
    /// <summary>
    ///  Represents a standard Windows label.
    /// </summary>
    [DefaultProperty(nameof(Text))]
    [DefaultBindingProperty(nameof(Text))]
    [Designer("System.Windows.Forms.Design.LabelDesigner, " + AssemblyRef.SystemDesign)]
    [ToolboxItem("System.Windows.Forms.Design.AutoSizeToolboxItem," + AssemblyRef.SystemDesign)]
    [SRDescription(nameof(SR.DescriptionLabel))]
    // If not for FormatControl, we could inherit from ButtonBase and get foreground images for free.
    public partial class Label : Control, IAutomationLiveRegion
    {
        private static readonly object s_eventTextAlignChanged = new object();

        private static readonly BitVector32.Section s_stateUseMnemonic = BitVector32.CreateSection(1);
        private static readonly BitVector32.Section s_stateAutoSize = BitVector32.CreateSection(1, s_stateUseMnemonic);
        private static readonly BitVector32.Section s_stateAnimating = BitVector32.CreateSection(1, s_stateAutoSize);
        private static readonly BitVector32.Section s_stateFlatStyle = BitVector32.CreateSection((int)FlatStyle.System, s_stateAnimating);
        private static readonly BitVector32.Section s_stateBorderStyle = BitVector32.CreateSection((int)BorderStyle.Fixed3D, s_stateFlatStyle);
        private static readonly BitVector32.Section s_stateAutoEllipsis = BitVector32.CreateSection(1, s_stateBorderStyle);

        private static readonly int s_propImageList = PropertyStore.CreateKey();
        private static readonly int s_propImage = PropertyStore.CreateKey();

        private static readonly int s_propTextAlign = PropertyStore.CreateKey();
        private static readonly int s_propImageAlign = PropertyStore.CreateKey();
        private static readonly int s_propImageIndex = PropertyStore.CreateKey();

        private BitVector32 _labelState;
        private int _requestedHeight;
        private int _requestedWidth;
        private LayoutUtils.MeasureTextCache _textMeasurementCache;

        // Tooltip is shown only if the Text in the Label is cut.
        internal bool _showToolTip;
        private ToolTip _textToolTip;

        // This bool suggests that the User has added a toolTip to this label. In such a case we should not show the
        // AutoEllipsis tooltip.
        private bool _controlToolTip;

        private AutomationLiveSetting _liveSetting;

        /// <summary>
        ///  Initializes a new instance of the <see cref='Label'/> class.
        /// </summary>
        public Label() : base()
        {
            // this class overrides GetPreferredSizeCore, let Control automatically cache the result
            SetExtendedState(ExtendedStates.UserPreferredSizeCache, true);

            SetStyle(ControlStyles.UserPaint |
                     ControlStyles.SupportsTransparentBackColor |
                     ControlStyles.OptimizedDoubleBuffer, IsOwnerDraw());

            SetStyle(ControlStyles.FixedHeight |
                     ControlStyles.Selectable, false);

            SetStyle(ControlStyles.ResizeRedraw, true);

            CommonProperties.SetSelfAutoSizeInDefaultLayout(this, true);

            _labelState[s_stateFlatStyle] = (int)FlatStyle.Standard;
            _labelState[s_stateUseMnemonic] = 1;
            _labelState[s_stateBorderStyle] = (int)BorderStyle.None;

            TabStop = false;
            _requestedHeight = Height;
            _requestedWidth = Width;
        }

        /// <summary>
        ///  Indicates whether the control is automatically resized to fit its contents.
        /// </summary>
        [SRCategory(nameof(SR.CatLayout))]
        [DefaultValue(false)]
        [RefreshProperties(RefreshProperties.All)]
        [Localizable(true)]
        [SRDescription(nameof(SR.LabelAutoSizeDescr))]
        [Browsable(true)]
        [EditorBrowsable(EditorBrowsableState.Always)]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
        public override bool AutoSize
        {
            get => base.AutoSize;
            set
            {
                if (AutoSize != value)
                {
                    base.AutoSize = value;
                    AdjustSize();
                }
            }
        }

        [SRCategory(nameof(SR.CatPropertyChanged))]
        [SRDescription(nameof(SR.ControlOnAutoSizeChangedDescr))]
        [Browsable(true)]
        [EditorBrowsable(EditorBrowsableState.Always)]
        new public event EventHandler AutoSizeChanged
        {
            add => base.AutoSizeChanged += value;
            remove => base.AutoSizeChanged -= value;
        }

        /// <summary>
        ///  This property controls the activation handling of bleedover for the text that
        ///  extends beyond the width of the label.
        /// </summary>
        [SRCategory(nameof(SR.CatBehavior))]
        [DefaultValue(false)]
        [Browsable(true)]
        [EditorBrowsable(EditorBrowsableState.Always)]
        [SRDescription(nameof(SR.LabelAutoEllipsisDescr))]
        public bool AutoEllipsis
        {
            get => _labelState[s_stateAutoEllipsis] != 0;
            set
            {
                if (AutoEllipsis != value)
                {
                    _labelState[s_stateAutoEllipsis] = value ? 1 : 0;
                    MeasureTextCache.InvalidateCache();

                    OnAutoEllipsisChanged(/*EventArgs.Empty*/);

                    if (value)
                    {
                        if (_textToolTip is null)
                        {
                            _textToolTip = new ToolTip();
                        }
                    }

                    if (ParentInternal is not null)
                    {
                        LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.AutoEllipsis);
                    }

                    Invalidate();
                }
            }
        }

        /// <summary>
        ///  Gets or sets the image rendered on the background of the control.
        /// </summary>
        [SRCategory(nameof(SR.CatAppearance))]
        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        [SRDescription(nameof(SR.LabelBackgroundImageDescr))]
        public override Image BackgroundImage
        {
            get => base.BackgroundImage;
            set => base.BackgroundImage = value;
        }

        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        new public event EventHandler BackgroundImageChanged
        {
            add => base.BackgroundImageChanged += value;
            remove => base.BackgroundImageChanged -= value;
        }

        /// <summary>
        ///  Gets or sets the image layout for the background of the control.
        /// </summary>
        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        public override ImageLayout BackgroundImageLayout
        {
            get => base.BackgroundImageLayout;
            set => base.BackgroundImageLayout = value;
        }

        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        new public event EventHandler BackgroundImageLayoutChanged
        {
            add => base.BackgroundImageLayoutChanged += value;
            remove => base.BackgroundImageLayoutChanged -= value;
        }

        /// <summary>
        ///  Gets or sets the border style for the control.
        /// </summary>
        [SRCategory(nameof(SR.CatAppearance))]
        [DefaultValue(BorderStyle.None)]
        [DispId((int)Ole32.DispatchID.BORDERSTYLE)]
        [SRDescription(nameof(SR.LabelBorderDescr))]
        public virtual BorderStyle BorderStyle
        {
            get => (BorderStyle)_labelState[s_stateBorderStyle];
            set
            {
                SourceGenerated.EnumValidator.Validate(value);

                if (BorderStyle != value)
                {
                    _labelState[s_stateBorderStyle] = (int)value;
                    if (ParentInternal is not null)
                    {
                        LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.BorderStyle);
                    }

                    if (AutoSize)
                    {
                        AdjustSize();
                    }

                    RecreateHandle();
                }
            }
        }

        /// <summary>
        ///  Determines whether the current state of the control allows for rendering text using TextRenderer (GDI).
        ///  See LinkLabel implementation for details.
        /// </summary>
        internal virtual bool CanUseTextRenderer => true;

        /// <summary>
        ///  Overrides Control.  A Label is a Win32 STATIC control, which we setup here.
        /// </summary>
        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;
                cp.ClassName = ComCtl32.WindowClasses.WC_STATIC;

                if (OwnerDraw)
                {
                    // An unfortunate side effect of this style is Windows sends us WM_DRAWITEM
                    // messages instead of WM_PAINT, but since Windows insists on repainting
                    // *without* a WM_PAINT after SetWindowText, I don't see much choice.
                    cp.Style |= (int)User32.SS.OWNERDRAW;

                    // Since we're owner draw, I don't see any point in setting the
                    // SS_CENTER/SS_RIGHT styles.
                    cp.ExStyle &= ~(int)User32.WS_EX.RIGHT;   // WS_EX_RIGHT overrides the SS_XXXX alignment styles
                }

                if (!OwnerDraw)
                {
                    switch (TextAlign)
                    {
                        case ContentAlignment.TopLeft:
                        case ContentAlignment.MiddleLeft:
                        case ContentAlignment.BottomLeft:
                            cp.Style |= (int)User32.SS.LEFT;
                            break;
                        case ContentAlignment.TopRight:
                        case ContentAlignment.MiddleRight:
                        case ContentAlignment.BottomRight:
                            cp.Style |= (int)User32.SS.RIGHT;
                            break;
                        case ContentAlignment.TopCenter:
                        case ContentAlignment.MiddleCenter:
                        case ContentAlignment.BottomCenter:
                            cp.Style |= (int)User32.SS.CENTER;
                            break;
                    }
                }
                else
                {
                    cp.Style |= (int)User32.SS.LEFT;
                }

                switch (BorderStyle)
                {
                    case BorderStyle.FixedSingle:
                        cp.Style |= (int)User32.WS.BORDER;
                        break;
                    case BorderStyle.Fixed3D:
                        cp.Style |= (int)User32.SS.SUNKEN;
                        break;
                }

                if (!UseMnemonic)
                {
                    cp.Style |= (int)User32.SS.NOPREFIX;
                }

                return cp;
            }
        }

        protected override ImeMode DefaultImeMode => ImeMode.Disable;

        protected override Padding DefaultMargin => new Padding(3, 0, 3, 0);

        /// <summary>
        ///  Deriving classes can override this to configure a default size for their control.
        ///  This is more efficient than setting the size in the control's constructor.
        /// </summary>
        protected override Size DefaultSize => new Size(100, AutoSize ? PreferredHeight : 23);

        [SRCategory(nameof(SR.CatAppearance))]
        [DefaultValue(FlatStyle.Standard)]
        [SRDescription(nameof(SR.ButtonFlatStyleDescr))]
        public FlatStyle FlatStyle
        {
            get => (FlatStyle)_labelState[s_stateFlatStyle];
            set
            {
                //valid values are 0x0 to 0x3
                SourceGenerated.EnumValidator.Validate(value);

                if (_labelState[s_stateFlatStyle] != (int)value)
                {
                    bool needRecreate = (_labelState[s_stateFlatStyle] == (int)FlatStyle.System) || (value == FlatStyle.System);

                    _labelState[s_stateFlatStyle] = (int)value;

                    SetStyle(ControlStyles.UserPaint
                             | ControlStyles.SupportsTransparentBackColor
                             | ControlStyles.OptimizedDoubleBuffer, OwnerDraw);

                    if (needRecreate)
                    {
                        // this will clear the preferred size cache - it's OK if the parent is null - it would be a NOP.
                        LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.BorderStyle);
                        if (AutoSize)
                        {
                            AdjustSize();
                        }

                        RecreateHandle();
                    }
                    else
                    {
                        Refresh();
                    }
                }
            }
        }

        /// <summary>
        ///  Gets or sets the image that is displayed on a <see cref='Label'/>.
        /// </summary>
        [Localizable(true)]
        [SRDescription(nameof(SR.ButtonImageDescr))]
        [SRCategory(nameof(SR.CatAppearance))]
        public Image Image
        {
            get
            {
                Image image = (Image)Properties.GetObject(s_propImage);

                if (image is null && ImageList is not null && ImageIndexer.ActualIndex >= 0)
                {
                    return ImageList.Images[ImageIndexer.ActualIndex];
                }
                else
                {
                    return image;
                }
            }
            set
            {
                if (Image != value)
                {
                    StopAnimate();

                    Properties.SetObject(s_propImage, value);
                    if (value is not null)
                    {
                        ImageIndex = -1;
                        ImageList = null;
                    }

                    // Hook up the frame changed event
                    //
                    Animate();
                    Invalidate();
                }
            }
        }

        /// <summary>
        ///  Gets or sets the index value of the images displayed on the
        ///  <see cref='Label'/>.
        /// </summary>
        [TypeConverter(typeof(ImageIndexConverter))]
        [Editor("System.Windows.Forms.Design.ImageIndexEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor))]
        [DefaultValue(ImageList.Indexer.DefaultIndex)]
        [Localizable(true)]
        [RefreshProperties(RefreshProperties.Repaint)]
        [SRDescription(nameof(SR.ButtonImageIndexDescr))]
        [SRCategory(nameof(SR.CatAppearance))]
        public int ImageIndex
        {
            get
            {
                if (ImageIndexer is not null)
                {
                    int index = ImageIndexer.Index;

                    if (ImageList is not null && (index >= ImageList.Images.Count))
                    {
                        return ImageList.Images.Count - 1;
                    }

                    return index;
                }

                return ImageList.Indexer.DefaultIndex;
            }
            set
            {
                if (value < ImageList.Indexer.DefaultIndex)
                {
                    throw new ArgumentOutOfRangeException(nameof(value), value, string.Format(SR.InvalidLowBoundArgumentEx, nameof(ImageIndex), value, ImageList.Indexer.DefaultIndex));
                }

                if (ImageIndex == value && value != ImageList.Indexer.DefaultIndex)
                {
                    return;
                }

                if (value != ImageList.Indexer.DefaultIndex)
                {
                    // Image.set calls ImageIndex = -1
                    Properties.SetObject(s_propImage, null);
                }

                ImageIndexer.Index = value;
                Invalidate();
            }
        }

        /// <summary>
        ///  Gets or sets the key accessor for the image list.  This specifies the image
        ///   from the image list to display on
        ///  <see cref='Label'/>.
        /// </summary>
        [TypeConverter(typeof(ImageKeyConverter))]
        [Editor("System.Windows.Forms.Design.ImageIndexEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor))]
        [DefaultValue(ImageList.Indexer.DefaultKey)]
        [Localizable(true)]
        [RefreshProperties(RefreshProperties.Repaint)]
        [SRDescription(nameof(SR.ButtonImageIndexDescr))]
        [SRCategory(nameof(SR.CatAppearance))]
        public string ImageKey
        {
            get => ImageIndexer?.Key;
            set
            {
                if (ImageKey == value && !string.Equals(value, ImageList.Indexer.DefaultKey))
                {
                    return;
                }

                // Image.set calls ImageIndex = -1
                Properties.SetObject(s_propImage, null);

                ImageIndexer.Key = value;
                Invalidate();
            }
        }

        internal LabelImageIndexer ImageIndexer
        {
            get
            {
                // Demand create the ImageIndexer property
                if ((!(Properties.GetObject(s_propImageIndex, out bool found) is LabelImageIndexer imageIndexer)) || (!found))
                {
                    imageIndexer = new LabelImageIndexer(this);
                    ImageIndexer = imageIndexer;
                }

                return imageIndexer;
            }
            set
            {
                Properties.SetObject(s_propImageIndex, value);
            }
        }

        /// <summary>
        ///  Gets or sets the images displayed in a <see cref='Label'/>.
        /// </summary>
        [DefaultValue(null)]
        [SRDescription(nameof(SR.ButtonImageListDescr))]
        [RefreshProperties(RefreshProperties.Repaint)]
        [SRCategory(nameof(SR.CatAppearance))]
        public ImageList ImageList
        {
            get => (ImageList)Properties.GetObject(s_propImageList);
            set
            {
                if (ImageList != value)
                {
                    EventHandler recreateHandler = new EventHandler(ImageListRecreateHandle);
                    EventHandler disposedHandler = new EventHandler(DetachImageList);

                    // Remove the previous imagelist handle recreate handler
                    ImageList imageList = ImageList;
                    if (imageList is not null)
                    {
                        imageList.RecreateHandle -= recreateHandler;
                        imageList.Disposed -= disposedHandler;
                    }

                    // Make sure we don't have an Image as well as an ImageList
                    if (value is not null)
                    {
                        Properties.SetObject(s_propImage, null); // Image.set calls ImageList = null
                    }

                    Properties.SetObject(s_propImageList, value);

                    // Add the new imagelist handle recreate handler
                    if (value is not null)
                    {
                        value.RecreateHandle += recreateHandler;
                        value.Disposed += disposedHandler;
                    }

                    Invalidate();
                }
            }
        }

        /// <summary>
        ///  Gets or sets the alignment of the image on the <see cref='Label'/>.
        /// </summary>
        [DefaultValue(ContentAlignment.MiddleCenter)]
        [Localizable(true)]
        [SRDescription(nameof(SR.ButtonImageAlignDescr))]
        [SRCategory(nameof(SR.CatAppearance))]
        public ContentAlignment ImageAlign
        {
            get
            {
                int imageAlign = Properties.GetInteger(s_propImageAlign, out bool found);
                if (found)
                {
                    return (ContentAlignment)imageAlign;
                }

                return ContentAlignment.MiddleCenter;
            }
            set
            {
                SourceGenerated.EnumValidator.Validate(value);

                if (value != ImageAlign)
                {
                    Properties.SetInteger(s_propImageAlign, (int)value);
                    LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.ImageAlign);
                    Invalidate();
                }
            }
        }

        /// <summary>
        ///  Indicates the "politeness" level that a client should use
        ///  to notify the user of changes to the live region.
        /// </summary>
        [SRCategory(nameof(SR.CatAccessibility))]
        [DefaultValue(AutomationLiveSetting.Off)]
        [SRDescription(nameof(SR.LiveRegionAutomationLiveSettingDescr))]
        [Browsable(true)]
        [EditorBrowsable(EditorBrowsableState.Always)]
        public AutomationLiveSetting LiveSetting
        {
            get => _liveSetting;
            set
            {
                SourceGenerated.EnumValidator.Validate(value);
                _liveSetting = value;
            }
        }

        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        new public ImeMode ImeMode
        {
            get => base.ImeMode;
            set => base.ImeMode = value;
        }

        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        public new event EventHandler ImeModeChanged
        {
            add => base.ImeModeChanged += value;
            remove => base.ImeModeChanged -= value;
        }

        /// <hideinheritance/>
        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        public new event KeyEventHandler KeyUp
        {
            add => base.KeyUp += value;
            remove => base.KeyUp -= value;
        }

        /// <hideinheritance/>
        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        public new event KeyEventHandler KeyDown
        {
            add => base.KeyDown += value;
            remove => base.KeyDown -= value;
        }

        /// <hideinheritance/>
        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        public new event KeyPressEventHandler KeyPress
        {
            add => base.KeyPress += value;
            remove => base.KeyPress -= value;
        }

        internal LayoutUtils.MeasureTextCache MeasureTextCache
            => _textMeasurementCache ??= new LayoutUtils.MeasureTextCache();

        internal virtual bool OwnerDraw => IsOwnerDraw();

        /// <summary>
        ///  Gets the height of the control (in pixels), assuming a
        ///  single line of text is displayed.
        /// </summary>
        [SRCategory(nameof(SR.CatLayout))]
        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Advanced)]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        [SRDescription(nameof(SR.LabelPreferredHeightDescr))]
        public virtual int PreferredHeight => PreferredSize.Height;

        /// <summary>
        ///  Gets the width of the control (in pixels), assuming a single line
        ///  of text is displayed.
        /// </summary>
        [SRCategory(nameof(SR.CatLayout))]
        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Advanced)]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        [SRDescription(nameof(SR.LabelPreferredWidthDescr))]
        public virtual int PreferredWidth => PreferredSize.Width;

        /// <summary>
        ///  Indicates whether
        ///  the container control background is rendered on the <see cref='Label'/>.
        /// </summary>
        [Obsolete("This property has been deprecated. Use BackColor instead.  https://go.microsoft.com/fwlink/?linkid=14202")]
        virtual new protected bool RenderTransparent
        {
            get => ((Control)this).RenderTransparent;
            set { }
        }

        private bool SelfSizing => CommonProperties.ShouldSelfSize(this);

        /// <summary>
        ///  Gets or sets a value indicating whether the user can tab to the
        ///  <see cref='Label'/>.
        /// </summary>
        [DefaultValue(false)]
        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        new public bool TabStop
        {
            get => base.TabStop;
            set => base.TabStop = value;
        }

        [Browsable(false)]
        [EditorBrowsable(EditorBrowsableState.Never)]
        new public event EventHandler TabStopChanged
        {
            add => base.TabStopChanged += value;
            remove => base.TabStopChanged -= value;
        }

        /// <summary>
        ///  Gets or sets the
        ///  horizontal alignment of the text in the control.
        /// </summary>
        [SRDescription(nameof(SR.LabelTextAlignDescr))]
        [Localizable(true)]
        [DefaultValue(ContentAlignment.TopLeft)]
        [SRCategory(nameof(SR.CatAppearance))]
        public virtual ContentAlignment TextAlign
        {
            get
            {
                int textAlign = Properties.GetInteger(s_propTextAlign, out bool found);
                if (found)
                {
                    return (ContentAlignment)textAlign;
                }

                return ContentAlignment.TopLeft;
            }
            set
            {
                SourceGenerated.EnumValidator.Validate(value);

                if (TextAlign != value)
                {
                    Properties.SetInteger(s_propTextAlign, (int)value);
                    Invalidate();

                    // Change the TextAlignment for SystemDrawn Labels
                    if (!OwnerDraw)
                    {
                        RecreateHandle();
                    }

                    OnTextAlignChanged(EventArgs.Empty);
                }
            }
        }

        /// <summary>
        ///  Gets or sets the text in the Label. Since we can have multiline support
        ///  this property just overrides the base to pluck in the Multiline editor.
        /// </summary>
        [Editor("System.ComponentModel.Design.MultilineStringEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor)),
        SettingsBindable(true)]
        public override string Text
        {
            get => base.Text;
            set => base.Text = value;
        }

        [SRCategory(nameof(SR.CatPropertyChanged))]
        [SRDescription(nameof(SR.LabelOnTextAlignChangedDescr))]
        public event EventHandler TextAlignChanged
        {
            add => Events.AddHandler(s_eventTextAlignChanged, value);

            remove => Events.RemoveHandler(s_eventTextAlignChanged, value);
        }

        /// <summary>
        ///  Determines whether to use compatible text rendering engine (GDI+) or not (GDI).
        /// </summary>
        [DefaultValue(false)]
        [SRCategory(nameof(SR.CatBehavior))]
        [SRDescription(nameof(SR.UseCompatibleTextRenderingDescr))]
        public bool UseCompatibleTextRendering
        {
            get
            {
                if (CanUseTextRenderer)
                {
                    return UseCompatibleTextRenderingInt;
                }

                // Use compat text rendering (GDI+).
                return true;
            }
            set
            {
                if (UseCompatibleTextRenderingInt != value)
                {
                    UseCompatibleTextRenderingInt = value;
                    AdjustSize();
                }
            }
        }

        /// <summary>
        ///  Determines whether the control supports rendering text using GDI+ and GDI. This is provided for container
        ///  controls to iterate through its children to set <see cref="UseCompatibleTextRendering"/> to the same value
        ///  if the child control supports it.
        /// </summary>
        internal override bool SupportsUseCompatibleTextRendering => true;

        /// <summary>
        ///  Gets or sets a value indicating whether an ampersand (&amp;) included in the text of  the control.
        /// </summary>
        [SRDescription(nameof(SR.LabelUseMnemonicDescr))]
        [DefaultValue(true)]
        [SRCategory(nameof(SR.CatAppearance))]
        public bool UseMnemonic
        {
            get => _labelState[s_stateUseMnemonic] != 0;
            set
            {
                if (UseMnemonic != value)
                {
                    _labelState[s_stateUseMnemonic] = value ? 1 : 0;
                    MeasureTextCache.InvalidateCache();

                    // The size of the label need to be adjusted when the Mnemonic
                    // is set irrespective of auto-sizing
                    using (LayoutTransaction.CreateTransactionIf(AutoSize, ParentInternal, this, PropertyNames.Text))
                    {
                        AdjustSize();
                        Invalidate();
                    }

                    //set windowStyle directly instead of recreating handle to increase efficiency
                    if (IsHandleCreated)
                    {
                        int style = WindowStyle;
                        if (!UseMnemonic)
                        {
                            style |= (int)User32.SS.NOPREFIX;
                        }
                        else
                        {
                            style &= ~(int)User32.SS.NOPREFIX;
                        }

                        WindowStyle = style;
                    }
                }
            }
        }

        /// <summary>
        ///  Updates the control in response to events that could affect either
        ///  the size of the control, or the size of the text within it.
        /// </summary>
        internal void AdjustSize()
        {
            if (!SelfSizing)
            {
                return;
            }

            // the rest is here for RTM compat.

            // If width and/or height are constrained by anchoring, don't adjust control size
            // to fit around text, since this will cause us to lose the original anchored size.
            if (!AutoSize &&
                ((Anchor & (AnchorStyles.Left | AnchorStyles.Right)) == (AnchorStyles.Left | AnchorStyles.Right) ||
                 (Anchor & (AnchorStyles.Top | AnchorStyles.Bottom)) == (AnchorStyles.Top | AnchorStyles.Bottom)))
            {
                return;
            }

            // Resize control to fit around current text

            int saveHeight = _requestedHeight;
            int saveWidth = _requestedWidth;
            try
            {
                Size preferredSize = (AutoSize) ? PreferredSize : new Size(saveWidth, saveHeight);
                Size = preferredSize;
            }
            finally
            {
                _requestedHeight = saveHeight;
                _requestedWidth = saveWidth;
            }
        }

        internal void Animate() => Animate(!DesignMode && Visible && Enabled && ParentInternal is not null);

        internal void StopAnimate() => Animate(false);

        private void Animate(bool animate)
        {
            bool currentlyAnimating = _labelState[s_stateAnimating] != 0;
            if (animate != currentlyAnimating)
            {
                Image image = (Image)Properties.GetObject(s_propImage);
                if (animate)
                {
                    if (image is not null)
                    {
                        ImageAnimator.Animate(image, new EventHandler(OnFrameChanged));
                        _labelState[s_stateAnimating] = animate ? 1 : 0;
                    }
                }
                else
                {
                    if (image is not null)
                    {
                        ImageAnimator.StopAnimate(image, new EventHandler(OnFrameChanged));
                        _labelState[s_stateAnimating] = animate ? 1 : 0;
                    }
                }
            }
        }

        protected Rectangle CalcImageRenderBounds(Image image, Rectangle r, ContentAlignment align)
        {
            Size pointImageSize = image.Size;

            int xLoc = r.X + 2;
            int yLoc = r.Y + 2;

            if ((align & WindowsFormsUtils.AnyRightAlign) != 0)
            {
                xLoc = (r.X + r.Width - 4) - pointImageSize.Width;
            }
            else if ((align & WindowsFormsUtils.AnyCenterAlign) != 0)
            {
                xLoc = r.X + (r.Width - pointImageSize.Width) / 2;
            }

            if ((align & WindowsFormsUtils.AnyBottomAlign) != 0)
            {
                yLoc = (r.Y + r.Height - 4) - pointImageSize.Height;
            }
            else if ((align & WindowsFormsUtils.AnyTopAlign) != 0)
            {
                yLoc = r.Y + 2;
            }
            else
            {
                yLoc = r.Y + (r.Height - pointImageSize.Height) / 2;
            }

            return new Rectangle(xLoc, yLoc, pointImageSize.Width, pointImageSize.Height);
        }

        protected override AccessibleObject CreateAccessibilityInstance() => new LabelAccessibleObject(this);

        /// <summary>
        ///  Get StringFormat object for rendering text using GDI+ (Graphics).
        /// </summary>
        internal virtual StringFormat CreateStringFormat()
            => ControlPaint.CreateStringFormat(this, TextAlign, AutoEllipsis, UseMnemonic);

        private TextFormatFlags CreateTextFormatFlags()
            => CreateTextFormatFlags(Size - GetBordersAndPadding());

        /// <summary>
        ///  Get TextFormatFlags flags for rendering text using GDI (TextRenderer).
        /// </summary>
        internal virtual TextFormatFlags CreateTextFormatFlags(Size constrainingSize)
        {
            // PREFERRED SIZE CACHING:
            //
            // Please read if you're adding a new TextFormatFlag.
            // whenever something can change the TextFormatFlags used
            // MeasureTextCache.InvalidateCache() should be called so we can appropriately clear.

            TextFormatFlags flags = ControlPaint.CreateTextFormatFlags(this, TextAlign, AutoEllipsis, UseMnemonic);

            // Remove WordBreak if the size is large enough to display all the text.
            if (!MeasureTextCache.TextRequiresWordBreak(Text, Font, constrainingSize, flags))
            {
                // The effect of the TextBoxControl flag is that in-word line breaking will occur if needed, this happens when AutoSize
                // is false and a one-word line still doesn't fit the binding box (width).  The other effect is that partially visible
                // lines are clipped; this is how GDI+ works by default.
                flags &= ~(TextFormatFlags.WordBreak | TextFormatFlags.TextBoxControl);
            }

            return flags;
        }

        private void DetachImageList(object sender, EventArgs e) => ImageList = null;

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                StopAnimate();
                // Holding on to images and image list is a memory leak.
                if (ImageList is not null)
                {
                    ImageList.Disposed -= new EventHandler(DetachImageList);
                    ImageList.RecreateHandle -= new EventHandler(ImageListRecreateHandle);
                    Properties.SetObject(s_propImageList, null);
                }

                if (Image is not null)
                {
                    Properties.SetObject(s_propImage, null);
                }

                //Dispose the tooltip if one present..
                if (_textToolTip is not null)
                {
                    _textToolTip.Dispose();
                    _textToolTip = null;
                }

                _controlToolTip = false;
            }

            base.Dispose(disposing);
        }

        private void DrawImage(PaintEventArgs e, Image image, Rectangle r, ContentAlignment align)
        {
            if (GetType() == typeof(Label))
            {
                // We're not overridden, use the internal graphics accessor as we know it won't be modified.
                DrawImage(e.GraphicsInternal, image, r, align);
            }
            else
            {
                DrawImage(e.Graphics, image, r, align);
            }
        }

        /// <summary>
        ///  Draws an <see cref='Drawing.Image'/> within the specified bounds.
        /// </summary>
        protected void DrawImage(Graphics g, Image image, Rectangle r, ContentAlignment align)
            => DrawImageInternal(g, image, r, align);

        private void DrawImageInternal(Graphics g, Image image, Rectangle r, ContentAlignment align)
        {
            Rectangle loc = CalcImageRenderBounds(image, r, align);

            if (!Enabled)
            {
                ControlPaint.DrawImageDisabled(g, image, loc.X, loc.Y, BackColor);
            }
            else
            {
                g.DrawImage(image, loc.X, loc.Y, image.Width, image.Height);
            }
        }

        private Size GetBordersAndPadding()
        {
            Size bordersAndPadding = Padding.Size;

            // COMPAT: Everett added random numbers to the height of the label
            if (UseCompatibleTextRendering)
            {
                //Always return the Fontheight + some buffer else the Text gets clipped for Autosize = true..
                if (BorderStyle != BorderStyle.None)
                {
                    bordersAndPadding.Height += 6; // taken from Everett.PreferredHeight
                    bordersAndPadding.Width += 2;  // taken from Everett.PreferredWidth
                }
                else
                {
                    bordersAndPadding.Height += 3; // taken from Everett.PreferredHeight
                }
            }
            else
            {
                // in Whidbey we'll actually ask the control the border size.

                bordersAndPadding += SizeFromClientSize(Size.Empty);
                if (BorderStyle == BorderStyle.Fixed3D)
                {
                    bordersAndPadding += new Size(2, 2);
                }
            }

            return bordersAndPadding;
        }

        public override Size GetPreferredSize(Size proposedSize)
        {
            // Make sure the behavior is consistent with GetPreferredSizeCore
            if (proposedSize.Width == 1)
            {
                proposedSize.Width = 0;
            }

            if (proposedSize.Height == 1)
            {
                proposedSize.Height = 0;
            }

            return base.GetPreferredSize(proposedSize);
        }

        internal virtual bool UseGDIMeasuring() => (FlatStyle == FlatStyle.System || !UseCompatibleTextRendering);

        // See ComboBox.cs GetComboHeight
        internal override Size GetPreferredSizeCore(Size proposedConstraints)
        {
            Size bordersAndPadding = GetBordersAndPadding();

            // Subtract border area from constraints
            proposedConstraints -= bordersAndPadding;

            // Keep positive
            proposedConstraints = LayoutUtils.UnionSizes(proposedConstraints, Size.Empty);

            Size requiredSize;

            if (string.IsNullOrEmpty(Text))
            {
                // Empty labels return the font height + borders
                using var hfont = GdiCache.GetHFONT(Font);
                using var screen = GdiCache.GetScreenHdc();

                // This is the character that Windows uses to determine the extent
                requiredSize = screen.HDC.GetTextExtent("0", hfont);
                requiredSize.Width = 0;
            }
            else if (UseGDIMeasuring())
            {
                TextFormatFlags format = FlatStyle == FlatStyle.System ? TextFormatFlags.Default : CreateTextFormatFlags(proposedConstraints);
                requiredSize = MeasureTextCache.GetTextSize(Text, Font, proposedConstraints, format);
            }
            else
            {
                // GDI+ rendering.
                using var screen = GdiCache.GetScreenDCGraphics();
                using StringFormat stringFormat = CreateStringFormat();
                SizeF bounds = (proposedConstraints.Width == 1) ?
                    new SizeF(0, proposedConstraints.Height) :
                    new SizeF(proposedConstraints.Width, proposedConstraints.Height);

                requiredSize = Size.Ceiling(screen.Graphics.MeasureString(Text, Font, bounds, stringFormat));
            }

            requiredSize += bordersAndPadding;

            return requiredSize;
        }

        /// <summary>
        ///  This method is to be called by LabelDesigner, using private reflection, to get the location of the text snaplines.
        /// </summary>
        private int GetLeadingTextPaddingFromTextFormatFlags()
        {
            if (!IsHandleCreated)
            {
                return 0;
            }

            // If we are using GDI+ the code below will not work, except/if the style is FlatStyle.System since GDI
            // will be used in that case.
            if (UseCompatibleTextRendering && FlatStyle != FlatStyle.System)
            {
                return 0;
            }

            TextFormatFlags flags = CreateTextFormatFlags();
            TextPaddingOptions padding = default;

            if ((flags & TextFormatFlags.NoPadding) == TextFormatFlags.NoPadding)
            {
                padding = TextPaddingOptions.NoPadding;
            }
            else if ((flags & TextFormatFlags.LeftAndRightPadding) == TextFormatFlags.LeftAndRightPadding)
            {
                padding = TextPaddingOptions.LeftAndRightPadding;
            }

            using var hfont = GdiCache.GetHFONT(Font);
            User32.DRAWTEXTPARAMS dtParams = hfont.GetTextMargins(padding);

            // This is actually leading margin.
            return dtParams.iLeftMargin;
        }

        private void ImageListRecreateHandle(object sender, EventArgs e)
        {
            if (IsHandleCreated)
            {
                Invalidate();
            }
        }

        /// <summary>
        ///  Specifies whether the control is willing to process mnemonics when hosted in an container ActiveX (Ax Sourcing).
        /// </summary>
        internal override bool IsMnemonicsListenerAxSourced => true;

        /// <summary>
        ///  This method is required because the Label constructor needs to know if the control is
        ///  OwnerDraw but it should not call the virtual property because if a derived class has
        ///  overridden the method, the derived class version will be called (before the derived
        ///  class constructor is called).
        /// </summary>
        private bool IsOwnerDraw() => FlatStyle != FlatStyle.System;

        /// <summary>
        ///  Raises the <see cref='Control.OnMouseEnter'/> event.
        /// </summary>
        protected override void OnMouseEnter(EventArgs e)
        {
            if (!_controlToolTip && !DesignMode && AutoEllipsis && _showToolTip && _textToolTip is not null)
            {
                try
                {
                    _controlToolTip = true;
                    _textToolTip.Show(WindowsFormsUtils.TextWithoutMnemonics(Text), this);
                }
                finally
                {
                    _controlToolTip = false;
                }
            }

            base.OnMouseEnter(e);
        }

        /// <summary>
        ///  Raises the <see cref='Control.OnMouseLeave'/> event.
        /// </summary>
        protected override void OnMouseLeave(EventArgs e)
        {
            if (!_controlToolTip && _textToolTip is not null && _textToolTip.GetHandleCreated())
            {
                _textToolTip.RemoveAll();

                _textToolTip.Hide(this);
            }

            base.OnMouseLeave(e);
        }

        private void OnFrameChanged(object o, EventArgs e)
        {
            if (Disposing || IsDisposed)
            {
                return;
            }

            if (IsHandleCreated && InvokeRequired)
            {
                BeginInvoke(new EventHandler(OnFrameChanged), o, e);
                return;
            }

            Invalidate();
        }

        protected override void OnFontChanged(EventArgs e)
        {
            MeasureTextCache.InvalidateCache();
            base.OnFontChanged(e);
            AdjustSize();
            Invalidate();
        }

        protected override void OnHandleDestroyed(EventArgs e)
        {
            base.OnHandleDestroyed(e);
            if (_textToolTip is not null && _textToolTip.GetHandleCreated())
            {
                _textToolTip.DestroyHandle();
            }
        }

        protected override void OnTextChanged(EventArgs e)
        {
            using (LayoutTransaction.CreateTransactionIf(AutoSize, ParentInternal, this, PropertyNames.Text))
            {
                MeasureTextCache.InvalidateCache();
                base.OnTextChanged(e);
                AdjustSize();
                Invalidate();
            }

            if (LiveSetting != AutomationLiveSetting.Off)
            {
                AccessibilityObject.RaiseLiveRegionChanged();
            }
        }

        protected virtual void OnTextAlignChanged(EventArgs e)
        {
            if (Events[s_eventTextAlignChanged] is EventHandler eh)
            {
                eh(this, e);
            }
        }

        protected override void OnPaddingChanged(EventArgs e)
        {
            base.OnPaddingChanged(e);
            AdjustSize();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            Animate();
            ImageAnimator.UpdateFrames(Image);

            Rectangle face = LayoutUtils.DeflateRect(ClientRectangle, Padding);
            Image i = Image;
            if (i is not null)
            {
                DrawImage(e, i, face, RtlTranslateAlignment(ImageAlign));
            }

            Color color;
            if (Enabled && SystemInformation.HighContrast)
            {
                color = SystemColors.WindowText;
            }
            else
            {
                using var hdc = new DeviceContextHdcScope(e);
                color = hdc.FindNearestColor(Enabled ? ForeColor : DisabledColor);
            }

            // Do actual drawing

            if (AutoEllipsis)
            {
                Rectangle clientRect = ClientRectangle;
                Size preferredSize = GetPreferredSize(new Size(clientRect.Width, clientRect.Height));
                _showToolTip = (clientRect.Width < preferredSize.Width || clientRect.Height < preferredSize.Height);
            }
            else
            {
                _showToolTip = false;
            }

            if (UseCompatibleTextRendering)
            {
                using StringFormat stringFormat = CreateStringFormat();
                if (Enabled)
                {
                    using var brush = color.GetCachedSolidBrushScope();
                    e.GraphicsInternal.DrawString(Text, Font, brush, face, stringFormat);
                }
                else
                {
                    ControlPaint.DrawStringDisabled(e.GraphicsInternal, Text, Font, color, face, stringFormat);
                }
            }
            else
            {
                TextFormatFlags flags = CreateTextFormatFlags();

                if (Enabled)
                {
                    TextRenderer.DrawTextInternal(e, Text, Font, face, color, flags: flags);
                }
                else
                {
                    //Theme specs -- if the backcolor is darker than Control, we use
                    // ControlPaint.Dark(backcolor).  Otherwise we use ControlDark.

                    Color disabledTextForeColor = TextRenderer.DisabledTextColor(BackColor);
                    TextRenderer.DrawTextInternal(e, Text, Font, face, disabledTextForeColor, flags: flags);
                }
            }

            base.OnPaint(e); // raise paint event
        }

        /// <summary>
        ///  Overriden by LinkLabel.
        /// </summary>
        internal virtual void OnAutoEllipsisChanged()
        {
        }

        protected override void OnEnabledChanged(EventArgs e)
        {
            base.OnEnabledChanged(e);
            Animate();
        }

        protected override void OnParentChanged(EventArgs e)
        {
            base.OnParentChanged(e);
            if (SelfSizing)
            {
                // In the case of SelfSizing
                // we don't know what size to be until we're parented
                AdjustSize();
            }

            Animate();
        }

        protected override void OnRightToLeftChanged(EventArgs e)
        {
            MeasureTextCache.InvalidateCache();
            base.OnRightToLeftChanged(e);
        }

        protected override void OnVisibleChanged(EventArgs e)
        {
            base.OnVisibleChanged(e);
            Animate();
        }

        private protected override void PrintToMetaFileRecursive(Gdi32.HDC hDC, IntPtr lParam, Rectangle bounds)
        {
            base.PrintToMetaFileRecursive(hDC, lParam, bounds);

            using var mapping = new DCMapping(hDC, bounds);
            using Graphics g = hDC.CreateGraphics();
            ControlPaint.PrintBorder(g, new Rectangle(Point.Empty, Size), BorderStyle, Border3DStyle.SunkenOuter);
        }

        /// <summary>
        ///  Overrides Control. This is called when the user has pressed an Alt-CHAR key combination and determines if
        ///  that combination is an interesting mnemonic for this control.
        /// </summary>
        protected internal override bool ProcessMnemonic(char charCode)
        {
            if (UseMnemonic && IsMnemonic(charCode, Text) && CanProcessMnemonic())
            {
                Control parent = ParentInternal;
                if (parent is not null)
                {
                    if (parent.SelectNextControl(this, true, false, true, false) && !parent.ContainsFocus)
                    {
                        parent.Focus();
                    }
                }

                return true;
            }

            return false;
        }

        /// <summary>
        ///  Overrides Control.setBoundsCore to enforce autoSize.
        /// </summary>
        protected override void SetBoundsCore(int x, int y, int width, int height, BoundsSpecified specified)
        {
            if ((specified & BoundsSpecified.Height) != BoundsSpecified.None)
            {
                _requestedHeight = height;
            }

            if ((specified & BoundsSpecified.Width) != BoundsSpecified.None)
            {
                _requestedWidth = width;
            }

            if (AutoSize && SelfSizing)
            {
                Size preferredSize = PreferredSize;
                width = preferredSize.Width;
                height = preferredSize.Height;
            }

            base.SetBoundsCore(x, y, width, height, specified);

            Debug.Assert(!AutoSize || (AutoSize && !SelfSizing) || Size == PreferredSize,
                "It is SetBoundsCore's responsibility to ensure Size = PreferredSize when AutoSize is true.");
        }

        private void ResetImage() => Image = null;

        private bool ShouldSerializeImage() => Properties.GetObject(s_propImage) is not null;

        /// <summary>
        ///  Called by ToolTip to poke in that Tooltip into this ComCtl so that the Native ChildToolTip is not exposed.
        /// </summary>
        internal override void SetToolTip(ToolTip toolTip)
        {
            if (toolTip is null || _controlToolTip)
            {
                return;
            }

            // Label now has its own Tooltip for AutoEllipsis.
            // So this control too falls in special casing.
            // We need to disable the LABEL AutoEllipsis tooltip and show
            // this tooltip always.
            _controlToolTip = true;
        }

        internal override bool SupportsUiaProviders => true;

        /// <summary>
        ///  Returns a string representation for this control.
        /// </summary>
        public override string ToString()
        {
            string s = base.ToString();
            return s + ", Text: " + Text;
        }

        /// <summary>
        ///  Overrides Control. This processes certain messages that the Win32 STATIC class would normally override.
        /// </summary>
        protected override void WndProc(ref Message m)
        {
            switch ((User32.WM)m.Msg)
            {
                case User32.WM.NCHITTEST:
                    // Label returns HT_TRANSPARENT for everything, so all messages get routed to the parent.  Change
                    // this so we can tell what's going on.

                    Rectangle rectInScreen = RectangleToScreen(new Rectangle(0, 0, Width, Height));
                    Point pt = new Point(unchecked((int)(long)m.LParam));
                    m.Result = (IntPtr)(rectInScreen.Contains(pt) ? User32.HT.CLIENT : User32.HT.NOWHERE);
                    break;

                default:
                    base.WndProc(ref m);
                    break;
            }
        }
    }
}
